Head mounted displays (HMDs) are used to provide virtual scenery to a user, or to augment real scenery with additional information or additional virtual objects. Stereoscopic images can be displayed e.g. by providing separate images to each eye of the user. In some HMD systems, at least one of a head or eye position and orientation of the user are tracked, and the displayed 3D scenery is adjusted in real time depending on the user's head orientation and gaze direction to provide an illusion of the user immersed into a simulated or augmented three-dimensional scenery.
A simulated scenery may have undesired distortions of three-dimensional perspective, focus anomalies, time lag, flicker, etc., which may cause nausea and visual fatigue of the viewer.